It is well known that exposed silver halides act as oxidizing agents, that the oxidized form of primary aromatic amine developing agents react with couplers to produce indophenols, indoanilines, indamines, azomethines, phenoxazines, phenazines and similar dyes, and that a colored image can be formed in this way.
The phenol based couplers or naphthol based couplers known as cyan colored image forming couplers from among these couplers have disadvantages in that the fastness with respect to heat or light of the colored image which is formed by color development is sometimes low, and reduced color densities arise in cases where a bleach bath (bleach-fix bath) which has a weak oxidizing power, or a exhausted bleach bath (bleach-fix bath), is used. Naphthol based cyan couplers which are substituted in the 5-position have been proposed in European Patent (Laid Open) 161,626A (corresponding to U.S. Pat. No. 4,690,889) as couplers which are improved in this respect. The cyan dyes formed from these couplers have excellent light and heat fastness, and they are excellent in that virtually no spectral absorbance of the colored dye depends on the color density. Furthermore, the conjoint use of ultraviolet absorbers has been suggested in JP-A-62-35356 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application") with a view to improving the yellow staining due to the irradiation of these couplers with light.
High boiling point organic solvents in which the couplers dissolve generally are used to form emulsified dispersions, but there is a problem in that sharpness deteriorates when the naphthol couplers disclosed in European Patent 161,626A are used in a large amount with respect to the couplers of the high boiling point organic solvents, as disclosed in JP-A-62-269958 (corresponding to EP-A-246,616).
However, it has been found that there is a pronounced reduction in color forming performance when photosensitive materials in which only a small amount of high boiling point organic solvent is used relative to these couplers are stored at very low temperatures, and the storage stability of the emulsified dispersions is poor unless a large amount of high boiling point organic solvent is used relative to the couplers.
On the other hand, JP-A-53-110528 proposed the use of specified ultraviolet absorbers and cyan couplers in the same layer. But the cyan couplers disclosed in JP-A-53-110528 do not exhibit any behavior at very low temperatures which is seen in the present invention and the ultraviolet absorbers used in the present invention are not necessarily those which are specified in JP-A-53-110528. Thus, the present invention has different constitution and effect from those of JP-A-53-110528. Surprisingly, when sensitive materials in which cyan couplers of the present invention are incorporated together with a very small amount of high boiling point organic solvent are stored at very low temperatures, there is reduction in the color forming ability. This phenomenon does not occur with couplers known in the past other than those of the present invention.